From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753250AbdKIH6F (ORCPT ); Thu, 9 Nov 2017 02:58:05 -0500 Received: from mail-pg0-f68.google.com ([74.125.83.68]:49109 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753170AbdKIH52 (ORCPT ); Thu, 9 Nov 2017 02:57:28 -0500 X-Google-Smtp-Source: ABhQp+QUYJue16276Z7lKwz3sbSs7k6LWRyc0M0+h9wxc3FWZ/J18LsnVrTUbJRSLQhUiZyeRpRnZw== From: Stephane Eranian To: linux-kernel@vger.kernel.org Cc: acme@redhat.com, peterz@infradead.org, mingo@elte.hu, ak@linux.intel.com, kan.liang@intel.com, jolsa@redhat.com Subject: [PATCH v4 4/5] perf/record: add documentation for using PERF_SAMPLE_SKID_IP Date: Wed, 8 Nov 2017 23:57:12 -0800 Message-Id: <1510214233-2074-5-git-send-email-eranian@google.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1510214233-2074-1-git-send-email-eranian@google.com> References: <1510214233-2074-1-git-send-email-eranian@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds documentation to describe how to use the skid ip support with perf record. The sample type can be provided per event as follows: pmu_instance/...,skid-ip=1/ For instance on Intel X86: $ perf record -e cpu/event=0xc5,skid-ip=1/pp does record the precise address of retired branches and their target. Signed-off-by: Stephane Eranian --- tools/perf/Documentation/perf-record.txt | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 5a626ef666c2..f0e3636dc4be 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -57,6 +57,14 @@ OPTIONS FP mode, "dwarf" for DWARF mode, "lbr" for LBR mode and "no" for disable callgraph. - 'stack-size': user stack size for dwarf mode + - 'skid-ip' : boolean, captures the unmodified interrupt instruction pointer + (IP) in each sample. Usually with event-based sampling, the IP + has skid and rarely point to the instruction which caused the + event to overflow. On some architectures, the hardware can eliminate + the skid and perf_events returns it as the IP with precise sampling is + enabled. But for certain measurements, it may be useful to have both + the correct and skid ip. This option enable capturing the skid ip in + additional to the corrected ip. Default is: false See the linkperf:perf-list[1] man page for more parameters. -- 2.7.4